U.S. patent number 8,038,440 [Application Number 10/546,702] was granted by the patent office on 2011-10-18 for method for placing and manufacturing a dental superstructure, method for placing implants and accessories used thereby.
This patent grant is currently assigned to Materialise Dental N.V.. Invention is credited to Bart Filip Jos Swaelens, Carl Van Lierde, Luc Vrielinck.
United States Patent |
8,038,440 |
Swaelens , et al. |
October 18, 2011 |
**Please see images for:
( Certificate of Correction ) ** |
Method for placing and manufacturing a dental superstructure,
method for placing implants and accessories used thereby
Abstract
Methods for placing and manufacturing a dental superstructure,
and methods for placing implants and accessories used thereby.
Inventors: |
Swaelens; Bart Filip Jos
(Putte, BE), Vrielinck; Luc (Genk, BE), Van
Lierde; Carl (Leuven, BE) |
Assignee: |
Materialise Dental N.V.
(Leuven, BE)
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Family
ID: |
32930824 |
Appl.
No.: |
10/546,702 |
Filed: |
February 23, 2004 |
PCT
Filed: |
February 23, 2004 |
PCT No.: |
PCT/BE2004/000024 |
371(c)(1),(2),(4) Date: |
August 24, 2005 |
PCT
Pub. No.: |
WO2004/075771 |
PCT
Pub. Date: |
September 10, 2004 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20060093988 A1 |
May 4, 2006 |
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Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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60450672 |
Mar 3, 2003 |
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60495731 |
Aug 18, 2003 |
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Foreign Application Priority Data
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Feb 28, 2003 [BE] |
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2003/0132 |
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Current U.S.
Class: |
433/76 |
Current CPC
Class: |
A61C
13/0004 (20130101); A61C 13/0003 (20130101); A61C
1/084 (20130101) |
Current International
Class: |
A61C
3/02 (20060101) |
Field of
Search: |
;433/69,76,172,173,72,75,215,225,229,201.1 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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09400399 |
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640 322 |
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Mar 1995 |
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EP |
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2000-512868 |
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Oct 2000 |
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JP |
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WO 92/03984 |
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Mar 1992 |
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WO |
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WO 97/10770 |
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Mar 1997 |
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WO |
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WO |
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WO 2004/064660 |
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Aug 2004 |
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WO |
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WO 2004/065893 |
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Aug 2004 |
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WO |
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WO 2004/075771 |
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Sep 2004 |
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WO |
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WO 2005/053564 |
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Jun 2005 |
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WO |
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WO 2006/115841 |
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Nov 2006 |
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WO |
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WO 2007/134701 |
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Nov 2007 |
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WO |
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Other References
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Written Opinion of the International Searching Authority,
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PCT/EP2004/013435, completed Mar. 16, 2006. cited by other .
International Preliminary Report on Patentability for
PCT/FR2003/000667, completed Oct. 17, 2003. cited by other .
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2005. cited by other .
International Search Report for PCT/FR2003/000667, mailed Jul. 28,
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Klein et al., "Computer-Guided Surgery Utilizing a Computer-Milled
Surgical Template," Pract. Proced. Aesthet. Dent. 13(2): 165-169
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Primary Examiner: Rodriguez; Cris L
Assistant Examiner: Eide; Heidi M
Attorney, Agent or Firm: Clark & Elbing LLP
Parent Case Text
CROSS REFERENCE TO RELATED APPLICATIONS
This application is the U.S. National Stage of International
Application No. PCT/BE2004/000024, filed Feb. 23, 2004, which, in
turn, claims the benefit of Belgian patent application 2003/0132,
U.S. provisional patent application No. 60/450,672, and U.S.
provisional patent application No. 60/495,731 filed Feb. 28, 2003,
Mar. 3, 2003, and Aug. 18, 2003, respectively.
Claims
The invention claimed is:
1. A method for placing a dental superstructure, said method
comprising the steps of: placing on the jaw of a patient a drill
jig having several ducts with vertical openings for guidance of a
drill, wherein the ducts comprise a lateral opening for lateral
insertion of the drill and wherein the ducts comprise a thread on
the inside; laterally inserting the drill into at least one of the
ducts by passing a portion of the drill through the lateral
opening, wherein one of a series of interchangeable bushes
comprising an external thread corresponding to the thread on the
inside of the duct and different internal diameters for working
with different drill diameters is placed over the drill prior to
its insertion into the duct; and after the drill has been inserted
into the duct, placing the bush in the duct while drilling to
provide guidance of the drill.
2. The method according to claim 1, wherein the bushes are
unscrewed from the drill jig before implants of the dental
superstructure are placed, and implant holders for holding the
implants are provided, wherein the outer diameter of the implant
holders corresponds to the inner diameter of the bushes for
providing guidance of each implant when placed through the vertical
opening.
3. The method according to claim 1, wherein the drill jig is also
used as a positioning jig for positioning implants in a position
for fitting the dental superstructure.
4. The method according to claim 1, wherein use is at least made of
a positioning jig for positioning implants in a position for
fitting the dental superstructure, wherein the positioning jig is
adapted as an accessory to force the implants into a specific
position after they have been placed.
5. The method according to claim 4, wherein said positioning jig is
provided with at least one aperture for a screw, said aperture
adapted to be screwed into the implants, wherein said aperture has
such a funnel-like shape that, when the screw is tightened, the
accessory is forced into the specific position.
6. The method according to claim 4, wherein computer planning is
used to form at least a part of the drill jig and/or at least a
part of a molding piece for the drill jig.
7. The method according to claim 1, wherein use is at least made of
an intermediate positioning jig as an accessory which at least has
features adapted for connection to at least one implant that has
already been placed, and features forming a duct for a drill and/or
for an implant or features forming an implant placed on an implant
holder.
8. The method according to claim 1, wherein said drill jig is
formed by means of data obtained by scanning a patient being
provided with the dental superstructure and by means of a computer
planning using said data.
9. The method according to claim 8, wherein use is at least made of
one of the following or a combination of two or more of the
following elements: an accessory in the shape of a digital cast
representing the general shape of a bone and/or of gums, wherein
the positions of implants are represented, in particular by means
of implant replicas, holes or the like; an accessory in the shape
of a key with a part representing the shape of teeth and a part
which is a negative of at least a part of the shape of the gums; an
accessory in the shape of a mold piece with contour parts (A-B-C)
and possibly a shifted part (D-E) adjusted to the shape of the
teeth of the superstructure to be formed, and with contours (G-F)
representing the shape of holes for the implants and of the bone
respectively; an accessory in the shape of a piece made directly
out of a modelling material and which has the shape of the
superstructure or of a part thereof.
10. The method according to claim 1, wherein use is made of a key
representing a mold of teeth, which is obtained by means of a mold
on the basis of a diagnostic arrangement of the teeth, and wherein
use is made of a digital cast representing the general shape of a
bone together with gums, and in which the positions of implants are
represented, in particular by means of implant replicas, whereby
the key and the digital cast fit against one another.
11. The method according to claim 1, wherein the superstructure, a
frame of the superstructure, or a portion of either thereof is
built directly on the basis of digital data obtained from a
computer planning or from a scan of at least a portion of the
patient's teeth or jaw.
12. The method according to claim 11, wherein the superstructure,
or at least said part thereof, is realized by means of rapid
prototyping techniques.
13. The method according to claim 1, wherein the superstructure is
made prior to placement of implants, and wherein the superstructure
is fixed on the implants before they have grown in, either
immediately after or shortly after the placing of these implants,
whereby the superstructure functions as an element for the
application of an immediate loading technique.
Description
The present invention concerns a method for placing and
manufacturing a dental superstructure. This is a structure which is
fitted on implants, fixed in the bone of a patient, upon which
artificial teeth have been or are provided.
It is known that when a number of teeth have to be built on more
than one dental implant, a metal frame can be used to this end
which fits on the implants, upon which the teeth can then be
modeled in order to form the superstructure.
According to a conventional method for placing such a
superstructure, implants are provided in the jaw, after which they
are left to grow in for three to six months. After this
osseo-integration, a mold or cast is taken of these implants or top
pieces, called abutments, that have been fitted upon the latter.
With this mold, the dental laboratory will then manufacture the
superstructure with the accompanying teeth.
According to a known technique, use can hereby be made of an
overdenture, whereby a metal structure is fit on the implants and
the prosthesis is snapped in on this structure in order to form the
final superstructure.
Use can also be made of a fixed superstructure with a metal frame,
for example gold or cobalt chromium, which roughly already has the
shape of the teeth, and upon which porcelain teeth are made.
Traditionally, the implants are left to grow in for three to six
months, after which the gums are opened again and the
superstructure, made on the basis of molds of the positioned
implants, are fixed on the implants.
Recently, however, there is a tendency to refrain from letting the
implants grow in for three to six months, and to immediately put a
load on them, what is called `immediate loading`.
The superstructure is hereby made, according to the methods known
until now, by means of (i) a test arrangement in an articulator,
which is used to determine the positions of the teeth and (ii) a
mold of the implants in the mouth of the patient on the other
hand.
This mold has to be made with great precision and the
three-dimensional positions of the implants must be reproduced very
precisely in the superstructure, since the different implants or
the abutments provided upon them have to correspond exactly to the
different points of contact in the superstructure.
Thus, the dental laboratory can only start manufacturing the
superstructure after the mold has been taken. This implies that,
with the present methods, it is not possible to fix the
superstructure immediately after the implants have been placed,
since the laboratory requires a number of days or weeks to
manufacture it.
In order to solve this problem, a known technique is to use
prefabricated standard superstructures in the shape of a horseshoe.
According to this method, the normal operational flow is flipped
upside down. Instead of adjusting the superstructure to the
positioning of the implants, the implants are positioned in
function of the superstructure. To this end, a drill jig is
supplied with the superstructure. Both have a shape similar to that
of a horseshoe. The bone is milled off thus providing a flat
surface on which the drill jig is positioned. Next implant cavities
are drilled on the places indicated by the jig.
Such a method, however, has a number of major disadvantages. The
bone has to be milled off in order to allow positioning of the jig
on the bone. This way of working is drastic and implies loss of
bone, while in many cases the patients already lack bone.
Moreover, the shape of the jaw has to correspond to the shape of a
horseshoe. Even if a number of models are made in the shape of a
horseshoe, there will always be patients whose jaws do not have a
shape corresponding with any of the predefined standards.
Further, the position of the implant is determined by the fitting
jig. Consequently, the implant cavities will not always be drilled
in the best place and more often than not end up in suboptimal
places, for example where the bone is not very strong. Moreover, it
is only possible to place the implants in a parallel way, which is
not always the best position.
The present invention features a method for placing and
manufacturing a dental superstructure. This method does not have
the above-mentioned disadvantages and is simple and fast.
Therefore, the invention concerns a method for placing and
manufacturing a dental superstructure, whereby (i) a computer
planning is made of the position of the implants, (ii) one or
several accessories are made on the basis of the computer planning
by means of which the implants can be placed, and whereby (iii) on
these implants, after they have been placed, the superstructure is
fitted, characterized in that the superstructure is made, either
directly or indirectly, on the basis of computer planning, which
normally will be the same computer planning as described above.
By also realizing the superstructure on the basis of the computer
planning, several advantages and new possibilities are created.
Thus, for example, the superstructure can always be perfectly
adjusted to the position of the implants. Moreover, it is no longer
necessary to make direct molds from the patient after the implants
have been placed. Further, it is also possible to realize the
superstructure beforehand so, if required, it can be fitted on the
implants immediately after they have been placed.
Manufacturing the superstructure directly or indirectly on the
basis of a computer planning means that said computer planning is
used to either form molding pieces for manufacturing the
superstructure, to form the superstructure itself, or to form parts
of such molding pieces or of such a superstructure.
It should be noted that the present invention also features a
number of new techniques for placing one or more implants,
irrespective of whether or not these techniques are used in
combination with the production of a superstructure on the basis of
a computer planning. Thus, for example, the invention also features
a method for placing one or several implants, whereby a computer
planning is made with reference to the position of the implants
concerned, characterized in that, on the basis of this computer
planning, one or several accessories are made by means of which the
implants can be placed (i.e., drilling of the implant cavities and
implant guidance). The method is hereby further characterized in
that, for the aforesaid accessories, one or several accessories are
made and/or used, selected from the following list: an accessory in
the shape of a drill jig in which one or several ducts are formed
for drills, which are provided in the drill jig in function of the
computer planning; an accessory in the shape of a drill jig in
which one or several ducts are formed for drills, which are
provided in the drill jig in function of with respect to the
computer planning, whereby means are also used in combination with
at least one of these ducts, which make it possible to successively
work with different drill diameters in one and the same duct; an
accessory as in the preceding paragraph, whereby the ducts have
openings in which above-mentioned means can be placed, which make
it possible to successively work with different drill diameters and
whereby these means consist of interchangeable bushes with openings
or passages of different diameters; an accessory as in the
preceding paragraph, whereby the ducts are laterally open to allow
lateral insertion of a drill and whereby the interchangeable bushes
preferably are placed over the drill prior to insertion and placed
in the duct while drilling to provide guidance an accessory in the
shape of a drill jig which is configured such that it also serves
as a fitting jig; an accessory in the shape of a drill jig which is
configured such that it also serves as a positioning jig, and in
particular can be used to force the implants into the required
position after they have been placed; an accessory which is made as
a positioning jig which allows to force the forcing of the implants
into the required position after they have been placed; an
accessory according to any of the two preceding paragraphs, whereby
said the accessory is provided with passages for screws that can be
screwed into the implants, whereby these passages and the
accompanying screws have such a shape that, when the screws are
tightened, they can be forced into a specific position; an
accessory which is made as an intermediate positioning jig which
has at least features which allow for a connection with at least
one implant that has already been placed, and which also has
features forming a duct for a drill and/or an implant or features
forming an implant placed on an implant holder.
Other details and advantages of the invention will emerge from the
description that follows, as well as from the attached claims.
Naturally, the invention also concerns all of the parts described
hereafter, used for realizing the method, such as accessories (for
example, jigs, molding pieces, etc.).
Naturally, the invention also features a method for manufacturing
such accessories, characterized in that the above-mentioned
accessories are built by means of a computer planning.
With the intention of better showing the characteristics of the
invention, hereafter as example without any limiting character,
some preferred embodiments of a method for placing and
manufacturing a dental superstructure according to the invention
are described, with reference to the accompanying drawings, in
which:
FIG. 1 represents a cross-section of a scan prosthesis;
FIG. 2 represents the use of a drill jig as a fitting jig while the
method according to the invention is being applied;
FIG. 3 represents the use of a positioning jig which can be applied
according to a possibility of the invention;
FIG. 4 represents the use of an intermediate fitting jig which can
be applied according to a possibility of the invention;
FIG. 5 represents a part of a digital cast which may be used
according to the invention;
FIG. 6 represents the production and use of a digital key;
FIG. 7 shows how the key from FIG. 6 and the digital cast from FIG.
5 can be combined;
FIG. 8 shows the actual superstructure being fit;
FIGS. 9 to 11 further illustrate a technique which can be applied
according to the invention;
FIGS. 12 and 13 show a special embodiment of a drill jig according
to the invention, in combination with a drill, for two different
positions of the drill.
With the intention of realizing a superstructure, a diagnostic
setup of the future teeth will first be made. This is normally done
in an articulator, i.e. an appliance in which two teeth molds or
plaster models/casts can be positioned in correct relation to one
another enabling the simulation of realistic jaw movement. The
diagnostic setup is made on the plaster models of the remaining
teeth or gums that indicates the future positions of the teeth.
The same test arrangement is also copied in a radio-opaque material
in order to make a scan prosthesis 1, as represented in FIG. 1, the
purpose of which will become clear from the further
description.
According to a variant of the method, instead of realizing this
diagnostic setup in a mechanical articulator, the test arrangement
can also be made virtually, with a computer, by means of what is
called a `virtual articulator` which can simulate the movements of
the upper jaw in relation to the lower jaw.
In this case, the jaws of the patient or a cast thereof will be
scanned, for example with a laser scanner. The two scanned jaws are
positioned in relation to one another by registering the respective
teeth surfaces on each other, or by scanning one of the jaws with a
moldable paste on top of it, such that the surface of one jaw
corresponds exactly to the other jaw.
Next, teeth can be chosen from a digital library and positioned in
those places where teeth are missing.
After this preliminary stage, preferably as a first step of the
actual method, a computer planning is made in view of the placement
of the implants.
This can be done for example by first scanning the patient with a
computed tomography scanner, CT-scanner in short, and by simulating
the implants on the CT-scans, as described in the Belgian patent
No. 1.011.205.
It is useful that the patient is scanned with what is called a scan
prosthesis 1 as represented in FIG. 1. This is a copy of the loose
prosthesis of the patient or of the diagnostic setup made by means
of an articulator. This scan prosthesis 1, which is placed on the
gums or mucosa 2 during the scanning, is made of a radio-opaque
material which is thus visible in the CT-images, whereby the teeth
3 of this scan prosthesis 1 have another degree of opacity than the
base part 4 supported on the gums or the mucosa 2, which covers the
bone of the patient.
A typical embodiment is one in which the teeth 3 are made of
acrylic resin mixed with 30% of barium sulfate, while the rest of
the prosthesis 1 is made of a mixture of acrylic resin and 10% of
barium sulfate. This offers the advantage that the teeth 3 are
nicely visible in the CT-scan images and can thus be segmented
separately in a simple manner. In addition the shape of the gums 2
will also be visible, as the base part 4 of the scan prosthesis 1
can be identified and delineates the gums and its lower side
represents the shape of the gums. Furthermore, the shape of the
surface of the bone 5 is perfectly visible by means of the
CT-scan.
Next, a drill jig 6 is made in function of the aforesaid planning.
This drill jig can possibly also serve as a fitting jig, since the
implants 7 can be placed by means of it. Implant placement can
possibly also be done with a separate fitting jig.
The drill jig 6, and possibly the fitting jig, can for example be
made by means of Rapid Prototyping techniques, as described in the
Belgian patent No. 1.011.205.
According to FIG. 2, the drill jig 6 fits on part 8 of the bone 5
of the patient (after the gums 2 have been opened) and enables
pre-operative transferral of the drill directions in conformity
with the planning of the surgeon. To this end, the drill jig 6 has
ducts 9 for one or several drills 10.
It should be noted that the bone 5 may have a very irregular
surface. As the drill jig 6 is designed based on data coming from
the CT-scan, the part of the jig in contact with the bone will have
an inner surface 8 which always follows the shape of the irregular
surface very precisely. The result is that there will always be an
accurate positioning.
It should also be noted that, according to a variant, said drill
jig, fitting jig and possibly even said positioning jig, can be
provided with a contact part which is not or not solely designed to
be supported on the bone 5, but (also) cooperates with parts of the
gums 2 and/or remaining teeth of the patient
The drill jig 6 is used when drilling holes 11 for implants 7.
The drill jig 6 has been designed such that it can be used for all
implants 7. This drill jig 6 is put only once on the patient and is
possibly screwed down temporarily.
The ducts 9 are, as shown, preferably composed of several parts.
First, there are a number of guiding tubes 12, preferably in the
form of collars, which make up one piece, together with the contact
part of the drill jig 8. These tubes or collars 12 provide openings
or passages 13 in which a bush 14 is fixed, made, for example, of
metal. The bush 14 is screwed or glued in the opening 13 and
provided with screw thread 15 on the inside which makes it possible
for interchangeable bushes 16 with external thread 17 to be screwed
in.
By using bushes 16 having the same outer diameter but with
different internal diameters 18, it becomes possible to guide
drills 10 having different diameters. FIG. 2 represents two drills
10 having different diameters and two corresponding bushes 16.
If, as represented, the drill jig 6 is also used as a fitting jig,
all the bushes 16 are unscrewed from the drill jig 6 before the
implants 7 are placed, and implant holders 19--whose outer diameter
corresponds to the inner diameter of the bushes 14--are put on the
implants 7. When an implant 7 is placed through the opening 13, the
duct guides the implant 7.
Such an implant holder 17 can be realized in different ways. As
shown in FIG. 2, it may simply consist of a cylindrical body that
at its lower end, for example by means of a recess 20, connects,
for example, to the hexagon shaped screw 22 of the implant 7 on
fixture level 21, and has a groove 23 on its top side for placing a
screwdriver.
It is also possible to manufacture different drill jigs or fitting
jigs corresponding to a drilling sequence, whereby every jig is
used for guiding a single drill. According to this last method, a
different jig with the appropriate diameters for each of the drills
10 or for each type of implant 7 is placed on the patient one after
the other.
Drilling of the holes 11 and placing of the implants 7 "as such"
can never be performed with the required precision to allow
immediate placement of a premanufactured superstructure: the
implants 7 will be positioned accurately within a couple of tenths
of a millimeter at the most in relation with regards to the
planning.
In order to solve this problem, one can use intermediate discs or
glue/cement the superstructure on the implants 7 or abutments.
The problem is preferably solved according to the present invention
by means of positioning a jig 24 that draws the implants 7 nearer
and nearer to the correct place, as will be further explained
hereafter by means of FIG. 3. A combination of the preceding
manners is also possible.
The positioning jig 24 is manufactured in function of the computer
planning of the implants 7, with technologies that offer the same
precision or possibly are identical to the ones used for
manufacturing the superstructure. It preferably consists, as shown
in FIG. 3, a body with apertures or passages 25 intended for screws
22 that can be screwed into the implants 7. These apertures 25 and
the accompanying screws 22, which needn't necessarily be the same
as in FIG. 2, have such a shape that, when the screws 22 are
tightened, they are forced into a specific position, such that the
implants 7 are aligned in relation to the positioning jig 24. To
this end funnel-shaped apertures 25 can be applied.
The positioning jig 24 is screwed onto the implants 7 in a
sequential manner. Because of the conical shape of the apertures 25
the implants 7 are forced into the desired position for fitting the
superstructure when the screws 22 are successively tightened.
The lower side of the positioning jig 24 must not necessarily be
adjusted to the shape of the bone 5 or possibly the gums 2 of the
patient. As the drilling and the implant placement have been done
in function of the patient, the positioning jig 24 is only
necessary for fine-tuning the positions. The small adjustments will
assure a perfect correspondence between the implants 7 and the
superstructure at fixture level or alternatively--if abutments are
used--at abutment level.
As shown, local supporting parts 26 may be provided on the lower
side of the positioning jig 24.
In principle, the positioning jig 24 may have the same overall
shape as the superstructure. It does not have teeth however.
Moreover, the positioning jig 24 may have guiding parts 27 where it
connects to the implants 7. These parts guide the implant fixtures
21 or the abutments placed upon them when the implants are drawn
into place.
In addition special abutments, can be placed on the implants 7.
Such abutments may have a ball joint on top of which a small with
internal threading (or similar) allows connection to other
structures to be made. This way, large angular deviations as well
as larger positioning errors can be rectified.
The function of the positioning jig 24 can also be assumed by the
superstructure itself. In this case, the superstructure will draw
the implants 7 into the required position. If the bone 5 is rather
soft, this will be done while the superstructure is being anchored
to the implants.
If the bone 5 is rather hard, for example in the lower jaw, the
implants 7 will not shift immediately. This will cause stresses in
the superstructure. However, these stresses will gradually
disappear, as the superstructure slowly makes the implants 7 shift.
Indeed the bone 5 will react to the strains caused by the implant
shift and will be slightly remodeled.
The positioning jig 24 can be manufactured by a number of
techniques, for example, computer-controlled CNC milling in metal
(CoCr, Ti, etc.), molding techniques based of on a master mold made
of wax, or CAD/CAM techniques.
Provided some minor adjustments are made, the positioning jig can
also be used as an intermediate fitting jig. This intermediate jig
can be used for all the implants 7, with the exception of those
that were placed first. Such an intermediate fitting jig 28 is
represented in FIG. 4.
When one, two or at the most three implants 7 have been placed with
the ordinary fitting jig, for example the combined drill
jig/fitting jig 6, the intermediate fitting jig 28 can be anchored
to those implants. The intermediate fitting jig 28 has features 29,
on the one hand, enabling a connection with implants 7 that have
already been placed, and features 30, on the other hand, which make
it possible to form a duct for one or several drills 10 and/or one
or several implant holders 19.
In the given example, the features 29 consist of openings or
passages 31 which can be made in a similar manner as the openings
25 and which make it possible for the fitting jig 28 to be fixed on
the implants 7 that have already been placed, by means of screws 22
or in any other way.
The features 30 include ducts 32 which are comparable to the ducts
9, in which a bush 14 can be provided that fit interchangeable
bushes 16, such that the ducts 32 can be used in an analogous
manner as the drill jig 6 from FIG. 4, both to guide drills for
making additional holes 11 and to guide the implants 7 during their
placement.
It is clear that in FIG. 4, only a part of the fitting jig 28 is
represented, and that, in reality, it will be fixed on at least two
implants 7 that have already been placed. As there is only a
limited number of implants 7, it is not difficult to fix the
intermediate fitting jig 28 upon them.
As a final step, the superstructure itself is manufactured in
function of the planning.
As the exact coordinates and directions of the implants are known,
the superstructure can be made with great accuracy. This may be
done for example by means of CNC processing or by means of CNC in
combination with traditional molding methods. An example of the
manufacture of such a superstructure 33 will be described hereafter
with reference to FIGS. 5 to 9.
A fixed superstructure 33 consists of two parts. A first part 34
fits on the implants 7 and is preferably designed and manufactured
by means of a digital mold cast 35, as will be further described in
detail. The second part 36, upon which the teeth 37 are modeled, is
produced by means of for example the digital articulator or a scan
prosthesis 1.
The digital cast 35, a part of which is represented in FIG. 5, as
well as a larger part in FIG. 7, can for example be made by means
of rapid prototyping on the basis of the digital data of the
aforesaid CT-scan and the computer planning. The scan prosthesis 1
hereby provides information about the gums 2, and the computer
planning provides information regarding the positioning of the
implants or any abutments fixed upon the latter. Thus, it is
possible to build such a digital cast 35, which is in fact a
one-piece model representing both the gums 2 and the bone 5 of the
patient.
Also, holes 38 are left in the digital cast 35--based on the
computer planning--in which implant replicas 39 can be fixed.
Thus, a model is obtained, having the shape of the gums 2, and in
which implant replicas 39 are found. This is exactly the same as a
traditional, manually made cast which is normally used in the
laboratory to produce a superstructure. The laboratory can thus,
continue working the way it is used to. It is for example, possible
to screw gold cylinders onto the replicas, cast a frame (for
example, a golden one), thus forming the above-mentioned part 34.
Other CAD/CAM techniques can be used by measuring the model again.
In order to obtain the desired shape of the teeth 37 in the
superstructure 33, a diagnostic setup 40 of the teeth 37 is made in
an articulator (FIG. 6). The teeth 37 are hereby placed in an
aesthetic manner in functional relation to both the antagonists and
the existing teeth in the same jaw half.
A mold of the teeth 37 in the setup 40 is made which will further
be referred to as `key` 41. This key 41 has a part 42 which
precisely delineates the gums 2.
By means of this key 41, the shape of the teeth 37 is transferred
to the digital cast 35, or possibly to a similar cast made in
another manner, by positioning said is key 41, as represented in
FIG. 7, on said cast. The key 41 fits on the digital cast 35, since
an identical shape of the gums 2 is used as the basis.
By positioning the mold, in particular, positioning the digital
cast 35 and the key 41 against one another and possibly by fixing
them against one another, an entire model is obtained which mimics
the surface of the gums 2 on the one hand, and which represents a
negative of at least the front side of the teeth 37 on the other
hand by means of the key 41. Based on this model, a dental
technician will be able to build the superstructure 33.
According to an important variant, the key 41 can also be built in
a digital manner on the basis of the computer planning. As the
shape of the teeth 37 and the shape of the gums 2 are known in the
digital model which has been made beforehand with the computer, it
is possible to realize a digital key, preferably by means of rapid
prototyping, analogous to the above-mentioned key 41, which thus
also fits on the digital cast 35, on the basis of said digital
model.
By taking an offset of the shape of the teeth 37, it is possible to
immediately realize the shape of the metal frame, or of the part
34. Taking an offset means that a key is realized in which the
surface corresponding to the outer shape of the teeth 37 is shifted
somewhat inwardly. Thus, it is possible to realize a metal shape
following the contour of the teeth 37 but situated somewhat more
inwardly. By then providing teeth plates upon it and/or by
providing a texture over it and/or a porcelain coating, it is
possible to provide teeth on the superstructure 33. This is also
indicated with reference 37, whose outer side corresponds to the
aimed shape.
Such an offset operation thus implies a design compensation to
allow an outer layer to be applied, for example made of porcelain,
on the metal part of the superstructure 33.
Possibly two digital keys could be manufactured, one corresponding
to the shape of the teeth and the other to the shape of the frame
to be realized.
Naturally, when manufacturing the superstructure 33 or a model
thereof which can subsequently be cast in metal, anchorage points
should be provided in the right places on the superstructure 33 to
allow the superstructure to be fixed onto the implants 7. As shown
in FIG. 7, little golden cylinders 43 may be placed on the replicas
39 to this end, around which the metal frame of the superstructure
33 is built. These cylinders 43 form openings which make it
possible to screw the thus manufactured superstructure 33 on the
implants 7 or to fix it upon them in another manner, as represented
in FIG. 8. The holes above the screws 44 are sealed with a filler
after fixation.
In fact, all sorts of molds and negatives of molds serving as an
accessory can be realized by means of computer planning according
to the invention, and it is not limited to the above-described
digital cast and digital key.
FIG. 9, for example, shows another variant of a mold piece 45 made
in an entirely digital manner by means of computer planning. The
contour of the part A-B-C represents the shape of a tooth, which is
known from the scan data obtained by scanning the scan prosthesis
1. On the basis thereof a contour D-E can be determined which has
been shifted slightly (e.g. which is offset in relation to the
contour B-C). Also the contour F of the bone 5 is known from the
scan data, while the contour G of the holes 11 is known from the
computer planning. Based on this information a mold piece 45 can
thus be built whose contour part A-D-C and the contours G and F can
be realized with great accuracy. The intermediate contour E-H can
be formed by filling the space 46, for example via thermojet.
On the basis of the then obtained mold piece 45 a piece 47, with a
section as given in FIG. 10, can be made in wax or another modeling
material. This piece 47 can then be cast in metal, so that a piece
48 as in FIG. 11 is obtained, upon which teeth plates or a
porcelain layer 49 can be provided in order to form the outer side
of the teeth of the superstructure 33.
According to yet another variant, the shape of the superstructure
itself or of a part thereof can be directly digitally converted to
a model, for example by realizing the piece 47 by means of direct
prototyping.
According to yet another possibility, the actual superstructure 33,
or at least the metal part thereof, is realized immediately by
using the digital data available via the scans and computer
planning, to for example form the metal frame of the superstructure
33 directly out of metal, for example by means of CAD/CAM
techniques. In practice, use can possibly be made to this end of a
five-axis milling technique in titanium.
FIGS. 12 and 13 show a special embodiment of a drill jig according
to the invention, wherein at least one duct 9 is laterally open, in
other words is provided with at least one lateral opening 50, which
opening allows the lateral insertion of a drill 10.
In case the duct 9 is provided with a collar 12 and a bush 14, the
opening 50 preferably extends through the wall of this collar 12
and bush 14.
Hereby, the above said interchangeable bushes 16 can be placed over
the drill 10 prior to insertion and placed in the duct 9 by sliding
and turning them over the drill 10 and/or automatically as a result
of the drilling action. Hereby the bushes 16 provide a guidance for
the drill 10.
The lateral opening 50 allows that the duct 9 is more easily
accessible by a drill 10.
It is clear that the drill jig 6 of FIGS. 12-13 can also be used as
a fitting and/or positioning jig.
It is also clear that, according to the invention, a drill jig 6
with such a lateral opening 50 can be applied in combination with
the above said methods for placing implants, as well as in
combination with any other method for placing implants, in which a
computer planning may be used or not.
Furthermore, it is clear too that such lateral opening 50 can be
used in combination with interchangeable bushes 16 or not.
Moreover, such opening 50 can be used in combination with bushes 14
or not, or can be used in combination with any other additional
accessories.
The present invention is by no means limited to the above-described
embodiments given as an example and represented in the accompanying
drawings; on the contrary, such a method for placing and
manufacturing a dental superstructure can be made in all sorts of
variants while still remaining within the scope of the
invention.
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